Food Hydrocolloids

Martin Glicksman

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367258757
• eBook ISBN: 9781000697391
• Topic: Technology & Engineering
• Subtopic: Biology
• Index: Technology & Engineering

First Published in 1982, this three-volume set explores the value of hydrocolloids in food. Carefully compiled and filled with a vast repertoire of notes, diagrams, and references this book serves as a useful reference for dieticians and other practitioners in their respective fields.

Comparative Properties of Hydrocolloids

Chapter 1

Origins and Classification of Hydrocolloids

Martin Glicksman

TABLE OF CONTENTS

I. Background and Terminology

II. Functional Properties

III. Structure and Functionality

A. Hydration and Solubilization

B. Types of Structures

1. Linear Polysaccharides

2. Branched Polysaccharides

IV. Origins of Hydrocolloids

A. Exudates

B. Extracts

C. Flours

D. Fermentation or Biosynthesis

E. Chemical Modification

F. Chemical Synthesis

V. Consumption and Availability

VI. Food Additive Regulations

References

I. Background and Terminology

Gums, hydrophilic colloids, hydrocolloids, mucilages, and water-soluble polymers are but a few designations for materials that have the ability to thicken or gel aqueous systems.^1-50 These materials were first found in exudates from trees or bushes, extracts from plants or seaweeds, flours from seeds or grains, gummy slimes from fermentation processes, and many other natural products. In more recent times, new and modified gums have been made by the chemical modification and derivatization of many of the natural gums. In addition, some very new gums were developed by complete chemical synthesis to yield new polymers having completely new and novel hydrophilic properties. A contemporary classification of edible gums or hydrocolloids based on origin and derivation is shown in Table 1.

Table 1
CLASSIFICATION OF EDIBLE HYDROCOLLOIDS

Exudates	Extracts	Flours	Biosynthetic or fermentation	Chemical modification	Synthetic
	Seaweed:	Seed:		Cellulose Derivatives:
Arabic	Agar	Guar	Dextran	Carboxymethylcellulose	Polyvinylpyrrolidone (PVP®)
Tragacanth	Alginates	Locust bean	Xanthan	Methylcellulose
Karaya	Carrageenans		Curdlan	Hydroxypropylcellulose	Carboxyvinyl polymers (Car-bopol®)
Ghatti	Furcellaran	Cereal:		Hydroxypropylmethylcellulose
	Land Plant:	Starches		Other Derivatives:
	Pectin	Microcrystalline cellulose		Modified starches	Polyethylene oxide polymers (PolyoxC®)
	Arabinoglactan			Low methoxyl pectin
	Animal:			Propylene glycol alginate
	Gelatin

The word “gum” itself means, a sticky substance, and is derived from the Egyptian term qemai or kami referring to the exudation of the Acanthus plant.⁶⁹

The adhesive qualities of these natural materials were known for thousands of years and the use of gums can be traced back to the dawn of history to the time of the caveman. The early caveman expressed his artistic abilities by daubing colored mud on the walls of his cave. To improve the adhesion of the “paint”, natural gum-like materials, such as crushed berries, milkweed sap, blood, eggs, milk, and dandelions were added. Subsequently the term “distemper” was used to refer to the mixture of pigment or color with glue or egg white instead of oil. The Egyptians in the period of 3000 to 2000 B.C. decorated the walls of their homes and temples with paintings executed in distemper. The use of vegetable gums such as gum arabic has continued to the present day in artists’ water colors.⁶⁸ The ancient Egyptians also used gums as adhesives for the wrappings employed in the ritual embalming of their mummies.

In addition to “stickiness” or “adhesiveness”, gums also were known for their thickening and gelling properties as well as for nutritional properties in specific cases. In the Orient, records dating back to the times of Confucius (about 800 to 600 B.C.) show the use of seaweeds and seaweed gums as components of various indigenous food preparations. In the Near East during Biblical times, locust beans (source of locust bean gum) were used for a minimal subsistence diet. St. John, during his wanderings in the wilderness, was reported to have survived on locust beans and to this day it is called St. John’s Bread in many parts of the world.

Over the centuries many natural plant exudates were discovered and the word “gum” was applied indiscriminately to all types of exudates; including such materials as chicle, rubber latex, rosin, benzoin, damar, copal, and a host of others. With time, the nomenclature and terminology of these natural products became more and more confusing and it was only in the post World War II period that a serious effort was made by scientists in this field to clarify and adopt a uniform terminology for these materials. Today, based on the works of Smith,⁴⁰ Montgomery,⁴⁰ Whistler,^{19, 32} Glicksman,^31,38-39 and others, a semblance of uniformity of terminology has been achieved and the current technical literature appears to be following the accepted guidelines.

Today, for practical purposes “gums” have been divided into two categories — water soluble and water insoluble. The water-insoluble exudates and polymers include chicle, rubber, rosin, etc., and are now referred to by the overall classification of “resins”.

The water-soluble materials are still referred to as “gums”, but this is gradually being replaced by the more scientific designation of “hydrophilic colloid”, preferably contracted to “hydrocolloid”.

Gums are not true colloids, but are rather polymers of colloid size (10Å to 1000Å) which exhibit the colloidal properties of remaining suspended under the influence of gravity, and of not being visible under microscopic examination. In fact, gums or hydrocolloids actually form molecular solutions in most instances.

Since most hydrocolloids are polysaccharides, progress towards a systematic nomenclature has produced the significant ending “...

Table of contents

• Cover
• Title Page
• Copyright Page
• Preface
• The Editor
• Contributors
• Dedication
• Table of Contents
• I. COMPARATIVE PROPERTIES OF HYDROCOLLOIDS
• II. FERMENTATION (BIOSYNTHETIC) GUMS
• INDEX